Apparatus and process for fractionating aib



Feb. 24, 1925. 1,527,639

G. R. FONDA APPARATUS AND PROCESS FOR FRACTIONATING' AIR Filed Sept. 20. 1918 /V/ TROGE/V COMPEESS 0R Inventor Govton R. Fonda Has Attorney.

Patented Feb. 24, fiiififiii.

BAWNT ow 3w YORK, sss ouosg To GENERAL iezoeoi mo oomi euwzg A oosronmiiou of NEW mink;-

sumulwus mar-o zeuoouss F03 'msomroumiv'iuo AER Appliaiion :uea' se teimier 20; 1915; :s'er'iioi'o: 2551,9912.

To all whom/it com'em':

Beit *knowii that Il',Gou'roN R; FounA, a citizen of the United Stots,' residing at Schenectady, in tho county of Schenectady, State of New Yoi'k hove invert-Tod cert-21in new and useful In'ihro'iiements in Appoifatus and Prooj'sesi foi" "Fi-imizioniitiii Air, of which tho foliov'ihg speoifioutiouf The presehtiuk ention-Comprises a p ocess and apparatus for hhoining eonceui'futes of o-igy'geii, lili'tl'ogfiii zivgoifi voni the air.

In my prior Poona ll'o lflihl zo, l: have desei ihed a process" and appa ifutus To? draw homin ziif whereiiy 2. iii uld oxy'geii oi'goii mixfiuhe is ohtkiihed ooiitiuuii'ig ab outI94 to 9670- 0xygen seiierallper' cent argon and. soroe nihrogeu, e d t-his hiixtui'e" is refoiified rate of fiowof om gae's through the apparaivus. v

Among the iardvim tziges of fthi s modified process are :-the recovery "from ihe'hir of a. higher 'peroeiituge of air oil; the productiou of a. niirogeoeohcehtrzlteof a higliilo greeoi' purity; the production of auiirgon concentra to adapted to he more many puri fled for comuiei die'vi use, these adwi nfziges being zit-pained with the produc tionfoi oxygen of the usual high grude' oi'comiiimuu puriij The" accompanying drawing illustrates somewhat diagrammatically one uppuruhis suitable for carrying out my invention. The apparatus inehivdes the rectification column 1 wherein liquid air is suh'jcoied to fractional distillation, and another distilhu tion column 2 wherein the gaseous mixture coming from column 1 is subjected to a seo 0nd fractional distillation.

I find that when liquid sir is subjected to rec-tiiicaiioo that ihe residual liquid after this process has been continued for u suificientdenfih bf time consisis hugely of'ozij gen; containing only about 1% or less, oi?

\ other gus,"and theguseous distillate cohsists iai 'el'y of nitrogen containing 'suhsiiamia-liy all of i-he'iirgoiufrom *c-ho'oi'ig'iual' u-ii' uud incirleumlly 'a small pcr centage of oxygen. Thomun and ox'yg'en 'oan ho sepdi'oiied from 'ihc hit-'rogen' by a. re-reoizificaiion 'in'h seizond rectifier yieldingu CQHUGDtZEI-tfi' consisting of oxflgoh, about 11 to 22% argon; amid a little nii rogcn.

Referringto the drawing; air coiiipi'essod in 'the usuiil'umimei' above the oribioehpi'eo sure is delivered fihi'ough a. conduit 3 undo coils toun QAPMESlC'HWWlY/Q The coil 4 preferably is surrounder; by pi eviousiy liquefied 'aiin' Whoii the cooled compressed uir ipusses through the expansion valve pzu t of it is liqiuzhed a ud isconveyed i'ay'tlre conduit (5 to the top of the i'eotification column 1. Tho operu-tiou of the lique fi er m PLOC'GEd in occoiduncefwith the usual Well 1 undeistm'id practice. Compressed air at the beginningof the ope-ration is expanded through the valve 5, thezeliy cooiing' thexaii'.

The cooled'uir'llesceuds in the coluu'm 1 and surrounds the coil 4. The cou'iiussed air thus being procoolcd issues "from the mop-unsion. Valve 'at ap-rogressively lower temper: tore until some of the exymudiuQ-"hir is liquefied. Afiei' the liquoiactiou has once been started only enough cooling by expan ommed occur to"compensate for heiit i1i. ilufx through. The Walls of the column 1. 'llie liquefied :iii' descends tlu'i'iugh the per-- formed boilie' plates 'l in coniuct with the vapor-s ascending from the liquid utthe foot ofth'e column. This liquid is boiled by "the lu-t'eut'heat which lihei aiod by the liquefaction. oil some of the coumiessed eiiin, (he coil 4. Gi'euiei' ie-lian'ce is placiui h the operator on clumieal zumlyses of the gases at different points in the column'iium on temperatures as indicated by bhei'iuoi'neiers. However. it may he si uied that in this firsi' coiun'iniho temperatures Will range from about K. at the bottom to about 79 ii. at the top, the pressure being kept at u few pounds above atmospheric pressure. The

rate of flow is adjusted until gaseous niirogen and argon constituents, containing e.

small amount of oxygen, leave the column 1.

A residue (-onsisfing of about 99% oxygen rerun .is 1111 the ioo't of the column. The )US i'nu iion ii; passed through a. conduit g n, oxygen, argon mixture is cooled in 8 into a compressor 9 This gaseous fraction consists largely of nitrogen and argon and should contain no more than about 2% oxygen It is conducted from the comresser into the coillOat the foot of the rec-j tification column 2. i The compressed nitgo t is coil 10 surrounded by a bath of liquefied gases and the cooled compressed mixture passes through a second expansion nozzle 11, where a second liquefaction of the gas oc curs. The liquid is carried through the condu it 12, to the top of oolurrm 2 where it dehe rectification in this column is regulated to yield substantially pure nitrogen gas through the conduit 14. which may be utilized for fixation processes, or any other industrial use requiring substantially pure nitrogen. The liquid collecting at the footof the column and escaping through the conduit 15 then consists almost entirely of argon and oxygen with a very small percentage of nitrogen, say, about 2%. This argon concentrate may be given-a chemical treatment, as, for example, heating in contact with copper or hydrogen in order to remove oxygen, and may then be used directly for commercial purposes, for example, as a filling in incandescent lamps.

What I claim as new and desire to secure by Letters Patent of the United States, is l. The process of lractionating air which consists in subjecting liquid air to fractional distillation until a gaseous distillate containing argon as well as nitrogen and :ygen is obtained, liquefying said gaseous \eitillate and subjecting the resulting liquid to a second fractional distillation, conductinlg away gaseous nitrogen and retaining a liquid residue consisting largely of oxygen and argon,

2. The process which consists in lime-:-

tic-nating liquid air by distillation until a column, a conduit for withdrawing a gaseous distillate near the top of said column, means for liquefying 'said distillate, and a second rectification column for independently fractionating the resulting liquid to yield substantially pure nitrogen and an argon concentrate.

4. A device for fractionating air to yield an argon concentrate which consists of the combination of means for fraction-sting air into two portions one of'which consists of substantially pure oxygen, the other portion comprising the nitrogen and argon, means for compressing and liquefyingsaid nitrogen-argon portion, a fractionating column, a conduit conveying said liquefied nitrogen-argon portion to said column to the exclusion of said oxygen portion, and a con 'duit for carrying away 'a nitrogen concentrat'e' from the top' of said column.

5. An appliratus for producing an argon concentrate whichcohsists in means for fractionating liquid air to produce substantially pure oxygen, a conduit forcarrying away 1 the gaseous residue consisting largely of nitrolgen containing substantially allot the argon, means for liquefying the same, means for fractionating said liquid independently of the oxygen into nitrogen, and an argon concentrate.

6. A process for producing an argon concentrate which. consists in rectifying liquid air to produce a substantially pure liquid oxygen, liqucl'ying the gaseous distillate and fractionating the resulting liquid until a residue is obtained containing about 11 to 22% argon, about 2% nitrogen, the balance being oxygen.

In witness whereof, I have hereunto set myliand this 19th day of September 1918.

GORTON IR. FONDA, 

